The invention relates to an open roof construction for a vehicle, comprising a roof opening formed in the roof of the vehicle, which can be closed by at least one closure element which can be moved forward and backward between an open position and a closed position.
With an open roof construction of the type to which the present invention relates, undesirable entry of wind into the opened roof opening forms a major problem. In the past, attempts have been made to prevent or at least minimize such wind entry.
It is an object of the present invention to provide a new way of preventing or at least minimizing such wind entry.
In order to accomplish that objective, the open roof construction according to the invention includes a flow-influencing flap mounted at a location of a part of the open roof construction which co-operates with a front edge of a closure element in the closed position of said closure element, which flap is pivotable about a pivot pin extending substantially transversely to the longitudinal axis (front to rear) of the vehicle, between a first position, in which it extends substantially parallel to the local air flow, and a second position, in which it extends at an angle with respect to the local air flow. Pivoting of the flap is prevented when the closure element is in a closed position, while pivoting of the flap to the second position, under the influence of the local air flow, is possible when the closure element is in an open position.
In the closed position of the closure element, said flap extends substantially parallel to the local air flow. This means that the flap does not encounter any appreciable resistance in this position, and that it hardly influences the air flow round the vehicle roof, if at all. As a matter of fact, such influencing of the flow is not necessary in this position, since the roof opening is closed by the closure element and wind entry is not possible. When the closure element has been moved to an open position, on the other hand, and the roof opening is open, the flap can pivot about its pivot pin to the second position, in which it extends at an angle with respect to the local air flow. As a result, the air flow is influenced in such a way that there is hardly any entry of wind into the open roof opening, if at all. Said pivoting of the flap to the second position takes place under the influence of the aforesaid local air flow. This means that such pivoting of the flap will thus occur only when there is a sufficiently strong local air flow. When the vehicle is stationary, for example, there is no such air flow, and the flap will take up the first position. Only when the vehicle starts to move will the flap be caused to pivot under the influence of the local air flow that occurs at that point in time.
The moment at which pivoting of the flap from the first position to the second takes place depends on various factors. The force of the local air flow plays a significant role, of course. In addition, the dimensions and the shape of the flap are important in this connection, as well as its location relative to the roof.
The co-operation between the local air flow and the flap can be realized in various ways. In accordance with a preferred embodiment of the open roof construction according to the invention, the flap thus comprises a part extending in front of the pivot pin, seen in the longitudinal direction of the vehicle, which part is in contact with the air flow and which, in the second position, extends at a positive angle with respect to the local flow at that location.
The result of the air flow acting on such a part extending in front of the pivot pin is that an angle of contact, once obtained, tends to become larger, so that the flap is automatically moved to the second position.
In this connection, it may furthermore be advantageous if the flap is provided with an inlet opening for the air flow at its front end, seen in the longitudinal direction of the vehicle. Such an inlet opening can be conducive to the cooperation between the air flow and the flap with a view to initiating the pivoting movement of the flap.
In another embodiment of the open roof construction according to the invention, the flap is fitted with a spring member, which loads the flap towards the first position. Such a spring member ensures that the flap will take up the first position, and remain in this position, for example when the vehicle is stationary or moving at a low speed. Uncontrolled vibration of the flap is prevented in a reliable manner under these circumstances. In that case the spring force (spring constant) determines the moment (force of the local flow) at which pivoting of the flap becomes possible.
Such a spring member may be a torsion spring acting round the pivot pin. Other constructional solutions are possible, however.
Furthermore, it is possible that the pivoting of the flap from the first position to the second position takes place upon exceeding a value of the air flow, which is higher than the value below which the air flow must decrease before the flap returns to the first position. This gives the flap a so-called hysteresis effect, thus preventing the flap from pivoting to and fro between the aforesaid two positions at certain limiting values, which is objectionable.
According to another embodiment, the flap is accommodated in a recess in the respective part of the open roof construction in its first position. On the one hand the aerodynamics of the open roof construction are optimized in this manner, while on the other hand it is possible to pay attention to the aesthetic aspect of the vehicle.
The flap can be mounted at various places. It is possible, for example, to mount the flap on the fixed roof of the vehicle, that is, at the front edge of the roof opening. In that case, the flap co-operates with the front edge of said closure element in the closed position of said closure element, and pivoting of the flap to the second position is possible only when the closure element is at least partially open.
It is also possible, however, to mount the flap on another part of the open roof construction, for example on a pivotable wind deflector. Such a pivotable wind deflector, which is known per se, will have said flap mounted on its free rear edge in that case. Pivoting of the flap is only possible once the rear edge of the wind deflector is no longer in contact with the front edge of the closure element. Such a situation can occur in several ways. The wind deflector itself may still be in its closed position, while the closure element is at least partially open. It is also possible for the closure element to be closed, while the wind deflector is at least partially open. In addition, both the wind deflector and closure element may be at least partially open.
According to another embodiment, the flap includes a part, which extends beyond the pivot pin. On the one hand such a part can perform a function in balancing the flap, but on the other hand such a part can also be used for engaging, in the first position of the flap, a closure element occupying its closed position. In that case the part in question functions to lock the flap in position.